Discussion message created

Fired when a message is posted in a discussion.

This event is fired when a message is posted in a discussion, including the messages your own agent posts.

message.type is the field to read, and its sense is the opposite of what you might expect on a Sidekick conversation: a person’s turn is OUTBOUND and your agent’s own replies return as INBOUND. An agent that answers every message it receives, without checking the type, answers itself forever. The custom agent guide has the full filter.

message.workspaceFiles holds the files attached to the message, and is present from webhook version 2026-09-02.

Schema

View JSON Schema →

Example:

{
  "timestamp": "2026-09-07T10:12:05.244Z",
  "workspaceId": "w_01HZ7QK3M9N4P5R6S7T8V9W0XY",
  "payload": {
    "eventType": "discussion.message_created",
    "discussion": {
      "id": "thd_01HZ8A1B2C3D4E5F6G7H8J9K0M",
      "type": "AGENT_SESSION",
      "agent": {
        "id": "mu_01HZ8B3C4D5E6F7G8H9J0K1M2N",
        "fullName": "Acme Support Agent",
        "publicName": "Acme Support",
        "description": "Answers billing questions in Sidekick",
        "createdAt": "2026-09-01T09:14:22.117Z",
        "createdBy": {
          "actorType": "user",
          "userId": "u_01HZ8C4D5E6F7G8H9J0K1M2N3P"
        },
        "updatedAt": "2026-09-01T09:14:22.117Z",
        "updatedBy": {
          "actorType": "user",
          "userId": "u_01HZ8C4D5E6F7G8H9J0K1M2N3P"
        },
        "deletedAt": null,
        "deletedBy": null
      },
      "status": "OPEN",
      "agentStatus": "IDLE",
      "threadId": "th_01HZ8N2P3Q4R5S6T7V8W9X0Y1Z"
    },
    "message": {
      "id": "thdm_01HZ8D5E6F7G8H9J0K1M2N3P4Q",
      "type": "OUTBOUND",
      "markdown": "Why did this customer's invoice fail?",
      "createdBy": {
        "actorType": "user",
        "userId": "u_01HZ8C4D5E6F7G8H9J0K1M2N3P"
      },
      "createdAt": "2026-09-07T10:12:05.198Z",
      "workspaceFiles": []
    }
  },
  "id": "pEv_01HZ8G8H9J0K1M2N3P4Q5R6S7T",
  "webhookMetadata": {
    "webhookTargetId": "whTarget_01HZ8K1M2N3P4Q5R6S7T8V9W0X",
    "webhookTargetVersion": "2026-09-06",
    "webhookDeliveryAttemptId": "whAttempt_01HZ8N3P4Q5R6S7T8V9W0X1Y2Z",
    "webhookDeliveryAttemptNumber": 1,
    "webhookDeliveryAttemptTimestamp": "2026-09-07T10:12:05.244Z"
  },
  "type": "discussion.message_created"
}

Using the Webhooks SDK

You can use the @team-plain/webhooks package to parse and verify this event with full type safety:

import { verifyPlainWebhook } from "@team-plain/webhooks";

const result = verifyPlainWebhook(rawBody, signature, secret);

if (result.error) {
  console.error(result.error.message);
} else {
  // result.data is fully typed with the event payload
  const event = result.data;
  console.log(event.eventType, event.payload);
}